Shrink huffman decode tables

libbz2-rs-sys/src/bzlib.rs

@@ -557,7 +557,7 @@ pub(crate) struct DState {
     pub len: [[u8; 258]; 6],
     pub limit: [[i32; 258]; 6],
     pub base: [[i32; 258]; 6],
-    pub perm: [[i32; 258]; 6],
+    pub perm: [[u16; 258]; 6],
     pub minLens: [u8; 6],
     pub save: SaveArea,
 }
@@ -571,12 +571,12 @@ pub(crate) struct SaveArea {
     pub alphaSize: u16,
     pub EOB: u16,
     pub groupNo: i32,
-    pub groupPos: u8,
-    pub nextSym: i32,
     pub nblock: u32,
     pub es: i32,
     pub zvec: i32,
+    pub nextSym: u16,
     pub nSelectors: u16,
+    pub groupPos: u8,
     pub zn: u8,
     pub nGroups: u8,
     pub curr: u8,

libbz2-rs-sys/src/decompress.rs

@@ -785,7 +785,7 @@ pub(crate) fn decompress(
                             Some(&nextSym) => nextSym,
                             None => error!(BZ_DATA_ERROR),
                         };
-                        if nextSym == BZ_RUNA as i32 || nextSym == BZ_RUNB as i32 {
+                        if nextSym == BZ_RUNA || nextSym == BZ_RUNB {
                             current_block = Block46;
                         } else {
                             es += 1;
@@ -842,10 +842,10 @@ pub(crate) fn decompress(
                 _ => {}
             }
             if current_block == Block40 {
-                if nextSym == EOB as i32 {
+                if nextSym == EOB {
                     current_block = Block41;
                 } else {
-                    if nextSym == 0 || nextSym == 1 {
+                    if nextSym == BZ_RUNA || nextSym == BZ_RUNB {
                         es = -1;
                         logN = 0;
                     } else if nblock >= 100000 * nblockMAX100k as u32 {
@@ -1116,7 +1116,7 @@ pub(crate) fn decompress(
                 if logN >= LOG_2MB {
                     error!(BZ_DATA_ERROR);
                 } else {
-                    let mul = match nextSym as u16 {
+                    let mul = match nextSym {
                         BZ_RUNA => 1,
                         BZ_RUNB => 2,
                         _ => 0,
@@ -1254,6 +1254,7 @@ pub(crate) fn decompress(
 
                     /*--- Create the Huffman decoding tables ---*/
                     for t in 0..nGroups as usize {
+                        // NOTE: s.nInUse <= 256, alphaSize <= 258
                         let len = &s.len[t][..alphaSize as usize];
 
                         let mut minLen = 32u8;

libbz2-rs-sys/src/huffman.rs

@@ -176,18 +176,20 @@ pub(crate) fn assign_codes(
 
 #[inline(always)]
 pub(crate) fn create_decode_tables(
-    limit: &mut [i32],
-    base: &mut [i32],
-    perm: &mut [i32],
+    limit: &mut [i32; 258],
+    base: &mut [i32; 258],
+    perm: &mut [u16; 258],
     length: &[u8],
     minLen: u8,
     maxLen: u8,
 ) {
+    assert!(length.len() <= 258);
+
     let mut pp: i32 = 0;
     for i in minLen..=maxLen {
         for (j, e) in length.iter().enumerate() {
             if *e == i {
-                perm[pp as usize] = j as i32;
+                perm[pp as usize] = j as u16;
                 pp += 1;
             }
         }